Stair construction



Jan. 27, 1931. w. DAVIS 1,789,969

sum cdnswnuc'rwn Filed July 6. 1929v rza Wi'bzeas T Patented Jan. 27,1931 UNITED srn'rrs WILLIAM A. DAVIS, OF MALDEN, MASSACHUSETTS, ASSIGNOBTO BABCOCK-D'AV IS COR- 2 PORATION, OF BOSTON, MASSACHUSETTS,ACORIORATION OF MASSACHUSETTS STAIR CONSTRUCTION Application filed July6, 1929. Serial No. 376,340.

The present invention relates to stair con-, struction, and moreparticularly to metallic stairs of the general form commonly employed inindustrial institutions and public buildings.

of which will be obvious to'those skilled in the art from the followingdescription.

In the accompanying drawings illustrating the preferred form of theinvention, Fig. 1v represents a side elevation, partially diagrammatic,of a stair embodying the improved features of the'invention; Fig. 2 is adetail illustrating a section in elevation of my improved stairconstruction; and Fig. 3 is a section on the line 33, Fig. 2.

The stair shown in the illustrated embodiment of the invention comprisesparallel stringer members 10 having upper and lower flanges 11 and 12,with the stringers mounted in such a manner that the lower'flanges aredirected inwardly and toward one another to serve as a. support for thestair treads. The stringers are supported at the upper and lower ends inany conventional or desired manner.

Each tread and riser comprises essentially a sheet-metal member 14,having a tread portion 16 and a riser portion 18, with an outwardlyturned nosing 20 at the upper end adapted to act as a reinforcement andsupport for the next adjacent tread. The individual stair member isrigidly connected at the junction of the tread and riser to the flange12 by means of a bolt or similar connection 22. The outwardly projectingledge formed by thenosing is also rigidly con nected to the nextadjacent tread 16 through securing bolts 24. In addition, each treadmember is rigidly connected to the face of the stringer at a pointadjacent the upper end of the tread through the employment of asupporting angle 26, which may be welded to the treadportion 16 at 28.After the individual stair member has been assembled between thestringers, the angle is bolted rigidly to the face of the stringer byconnections 30, all as indicated in Fig. 3. It-w'ill be evident that asecuring angle is provided at opposite sides of each tread for connection to both stringer members, one only of a these angles beingindicated in Fig. 3. By virtue of this construction not only are theindividualstair elements rigidly connected together at the outerportionof the tread, but in addition each stair element is rigidly connected tothe stringer members, both at the junction of the tread and riser and atpoints adjacent the outer end of the tread. After assembly of themetallic portion of the stair structure with the stringer members, thetread is conveniently filled to a level gauged by the height of thenosing 20 with a cementitious mixture 32, as indicated in Fig. 2, thismixture providing the necessary tread wearing surface covering the metalsupport.

With this construction it will be evident, furthermore, that thesecuring angles,due to their location in proximity to the faces of thestringers 10, leave a completely unobstructed and unbroken tread spacefor the reception of the cementitious mixture, and

permit the formation of a homogeneous mass of necessary depth which isnot intersected by securing bolts or other similar constructions whichmight conceivably weaken and cause premature cracking and failure of themixture forming the tread.

I claim:

A stairway comprising opposed stringer members, sheet metal stairelements each comprising a tread and riser interposed between thestringer members, an upwardly extended nosing at the front portlon ofeach tread, a cementitious mixture covering the tread to the approximatedepth of the nosing, and supporting angles Welded to the upper face ofeach sheet metal tread element and at opposite sides of the treadelement adjacent the front portion, and connections between the anglesand stringers for rigidly supporting the tread elements therefrom, thesupporting angles being embedded Within the cementitious mixturecovering the sheet metal tread.

' WILLIAM A. DAVIS.

